For purposes of this disclosure, a heat sink is any body of metal or like material placed in contact with an electronic device package for transferring heat through conduction from the semiconductor device contained in the electronic device package and rapidly dissipating such heat to the environment. One type of electronic device package is known as a gate array. A gate array includes a relatively thin square or rectangular housing containing a semiconductor device. A plurality of rigid leads are electrically connected to the semiconductor device and extend downwardly from a lower surface of the housing. The gate array is mounted on a printed circuit board by inserting each of the leads into an aligned preformed hole in the printed circuit board and soldering the lead therein.
Finned heat sinks have been found to be particularly effective when used with gate arrays. A finned heat sink consists of a central post having a plurality of spaced fins extending radially from the post. When one end of the post is mounted on the gate array housing, heat generated by the semiconductor device contained therein is conveyed through the post and dissipated into the environment by the large surface area presented by the fins.
Various means have been used in the past to attach a heat sink in intimate thermal contact with an electronic device package. It is known to glue or otherwise adhesively attach a heat sink to an electronic device package such as a gate array. However, assembly of a heat sink to the electronic device package is messy, tedious, labor intensive and therefore expensive and it is difficult to accurately align the heat sink with the electronic device package. This is particularly a problem when attaching a finned heat sink to a gate array. Many of the commonly used adhesives emit fumes or otherwise constitute an undesirable health hazard. Frequently, it is necessary to cure the glue at an elevated temperature for extended periods of time, further increasing the manufacturing costs. It is also sometimes desirable to remove the heat sink from the electronic device package for repair or replacement. This is extremely difficult, if not impossible, to accomplish when the heat sink is adhesively mounted on the electronic device package.